JEE Main20252 Apr 2025Evening ShiftMathematicsStatisticsActual

If the mean and the variance of 6,4, a, 8, b, 12,10 , 13 are 9 and 9.25 respectively, then a+b+a b is equal to :

Options

A105
B103
C100
D106

Correct answer

B. 103

Step-by-step solution

aligned & mean =9 & 53+ a + b =72 & a + b =19 & ^2= 37 4 and ( X )^2+ ^2= x ₁^2 ~N & 81+ 37 4 = 529+ a ^2+ b ^2 8 & 648+74=529+ a ^2+ b ^2 & a ^2+ b ^2=193 & a + b =19 a ^2+ b ^2+2 ab =361 & 2 ab =168 & ab =84 & a + b + ab =103 aligned

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